This invention relates in general to fiber-optic transmitter arrangements and more specifically to a novel laser controller circuit for a fiber-optic transmitter.
Fiber-optic receivers and transmitters or fiber-optic interface units are used in modern telecommunications and data transmission systems between an optical fiber transmission line and electronic digital equipment. The fiber-optic transmitter receives electrical signals from the electronic equipment representing the data to be transmitted. The transmitter then converts the data to light pulses which are coupled to an optical fiber transmission line. The fiber-optic receiver receives light pulses representing the transmitted data from an optical fiber transmission line and converts the light pulses to electrical signals which are sent to and processed by the electronic digital equipment. These systems work in very high transmission rates from 145Mbs to 2400Mbs (Megabits per second).
Transmission of data or other signals along optical fiber transmission lines have advantage in the fact that light rays are almost immune to electromagnetic interference such as sparks, lightening, crosstalk and other interference which may be induced into the transmission line.
Many fiber-optic transmitters use a high output solid state light emitting device or laser to produce the light pulses used in the transmission of data. The electrical signals received from the electronic equipment are input into a laser drive circuit which modulates the laser producing the light output signals.
In order to prolong the life and the efficiency of a high output laser some means must be provided to shut down the laser in cases where the laser drive fails. Further, it is also advantageous to able to monitor the laser's output and also to detect if the laser has failed.
It therefore becomes an object of the present invention to disclose a novel laser DC bias controller which monitors and controls the operation of the laser of a laser.